Group via oxide-alkaline earth metal hydride catalyzed polymerization of olefins



Jan- 17, 1956 E. FIELD ETAL 2,731,452

GROUP VI A OXIDE-ALKALINE EARTH METAL HYDRIDE CATALYZED POLYMERIZTION 0FOLEFINS Filed DEC. 6, 1952 FR c ABSORBEI? 57 REAOTO/P GUARD /5 CHAMBERINVENTORS- Edmund Fie/d u) BY Marr/s Fe//er Q M Us lu in A r rom/EyUnited States Patent O GROUP VIA OXIDE-ALKALINE EARTH METAL HYDRIDECATALYZED POLYMERIZATION F LEFINS Edmund Field and Morris Feller,Chicago, Ill., assignprs to Standard Oil Company, Chicago, Ill., acorporatlon of Indiana Application December 6, 1952, Serial No. 324,607

18 Claims. (Cl. 260-88.1)

This invention relates to a novel polymerization process;` In a morespecific aspect, this invention relates to a novel process for thepolymerization of ethylene, propylene or their mixtures in the presenceof a hydride of a metal selected from the group consisting of Be, Mg,Ca, Sr and Ba (non-radioactive metals of group 2a) and a solid catalyticmaterial containing an oxide of a metal of group 6a (left hand subgroupof group 6) of the Mendeleef Periodic Table, viz., one or more of theoxides of Cr, Mo, W or U.

One object of our invention is to provide novel and highly usefulcatalysts for the preparation of high molecular weight polymers fromethylene-containing gas mixtures. Another object is to provide a processof ethylene polymerization in which the yields of solid polymer aregreatly increased, as compared with the yields heretofore obtainablesolely by the use of subhexavalent molybdena catalysts and similarcatalysts. .Another object is to provide a novel process for thepolymerization of ethylene to high molecular weight normally solidpolymers. Still another object of our invention is to provide a novelprocess for the conversion of gas mixtures comprising essentiallyethylene to high molecular weight solid resinous or plastic materials.

A further object is to provide a relatively low ternperature, lowpressure process for the conversion of ethylene-containing gases to highmolecular weight resinous or plastic materials. An additional object ofthe present invention is to provide a process for the copolymerizationof ethylene with other polymerizable materials, particularly with anormally gaseous mono-olefin such as propylene, to provide novelresinous materials. Yet auother object of our invention is to provide aprocess for the preparation of solid, elastic polymers from propylene.These and otherobjects of our invention will become apparent from theensuing description thereof.

Brielly, the inventive process comprises the conversion of ethylene,propylene or their mixtures principally to high molecular weight`normally solid, resinous polymers by contact with a group 6a metaloxide, preferably supported on a difficultly reducble metal oxide, andone or more of the hydrides of Be, Mg, Ca, Sr and Ba. The inventiveprocess is effected at temperatures between about 75 C. and about 325C., preferably between about 130 C. and 260 C., and pressures betweenabout atmospheric and 15,000 p. s. i. g. or higher, preferably betweenabout 200 and 5000, or about 1000 p. s. i. g'. The normally solidmaterials produced by the catalytic conversion tend to accumulate uponand within the solid catalyst. It is desirable to supply to the reactionzone a liquid medium which serves both as a reaction medium and asolvent for the solid reaction products. Suitable liquid reaction mediafor polymerization include various hydrocarbons, particularly anaromatic hydrocarbon such as benzene, toluene or xyleues. For thepolymerization of propylene, I ess readily alkylatable reaction medasuch as cycloparains, e. g., cyclohexane or decalin,

or paraffins,`e. g., isooctane, are preferred. The conversion ofethylene or propylene can Vbe effected in the absence of a liquidreaction medium or solvent and the catalyst containing accumulated solidpolymeric conversion products can be treated from time to time, withinor outside the conversion zone, to eiect removal of conversion productstherefrom and, if necessary, reactivation or 'regeneration of thecatalyst for further use.

The practice of the process of the present invention leads to ethylenehomopolymers, propylene polymers and ethylene-propylene copolymers ofwidely variant molecular weight ranges and attendant physical andmechanical properties, dependent upon the selection of operatingconditions. The inventive process is vcharacterized by extremeilexibility both as regards operating conditions and as regards theproducts producible thereby. Thus the present process can be effectedover extremely broad ranges of temperature and pressure. The practice ofthe present process can lead to grease-like ethylene homopolymers havingan approximate molecular weight range of 300 to 700, Wax-like ethylenehomopolymers having an approximate specific viscosity (X) between about1000 and 10,000 and tough, resinous ethylene homopolymers having anapproximate specific viscosity (X105) of 10,000 to more than 300,000[(11 relative-l) l05]. By the term tough, resinous polyethylene as usedin the present specification and claims, we mean polymer having abrittle point below 50? C. (A. S. T. M. method D746-51T), impactstrength greater than two foot pounds per inch of notch (A. S. T. M.method D256-47TIzod machine) and minimum elongation at room temperature(25 C.) of 100%.

The process of the present invention can be employed to effect thecopolymerization of ethylene with other polymerizable materials andparticularly with propylene. Propylene alone has been polymerized, bythe employment of catalysts of the present invention, to elasticpolymers, in addition to oils and grease-like solids. polymerizablematerials include mono-olenic hydrocarbons such as n-butylenes,isobutylene, t-butylethy1ene,.

and the like, usually in proportions between about l and about 25% byweight, based on the weight of ethylene. The hydrides of calcium,strontium and barium are readily prepared by the interaction of hydrogenwith the f pure metals. Thus metallic calcium reacts readily withhydrogen at, 200 C. to produce CaHz. Calcium hydride can also beprepared by the reaction of nesium and hydrogen, which producescontaining-MgO. Strontium the reaction of a strontium halide withlithium aluminum hydride (A. E. Finholt et al., J. Am. Chem. Soc. 69, l199-1203 (1947)). Beryllium and magnesium hydrides calcium hydride canbe prepared by special methods known in the art.`

lt will be understood that the specific preparative methods involvedform no part of our invention and that any method which yields thedesired metal hydride can be employed. Usually the hydrides employedaccording to the present invention are prepared outside the reactor, butthey may be prepared in situ and polymerization can then be effected inthe reactor.

The employment of one or more of the hydrides of Be, Mg, Ca, Sr and Bain the reaction zone has numerous practical advantages, as compared toprocesses Wherein group 6a metal oxide catalysts are employed withoutsaid hydrides. Thus, when both the said hydrides and group 6a metaloxide catalysts are employed, high yields of solid polymers can beobtained from ethylene, the metal oxide-containing catalyst functionswell in the presence of large proportions of liquid reaction medium, themetal oxide-containing catalyst retains strong polymerization activityfor a long period of time (long catalyst life),

Other CaO with mag- '5 hydride can be prepared by`` at least in part, toa lower oxide.

polymers having desirable. ranges of physical and chemical. propertiescan be readily 'produced by controlling the reaction variables, etc., aswill appear from the detailed description and operating examples whichfollow.

Y The function or functions of the metal hydride in our process are notwell understood. The hydrides of Be, Mg, Ca, Sr and Ba alone are notcatalysts. for the polymerization of ethylene or propylene to yield highmolecular weight, normally solid polymers under the conditions describedherein. Yet, these metal hydrides cofunction somehow with the group 6ametal. oxide catalysts to increase the productivity (polymer yield) ofsaid catalysts, sometimes prodigiously. It mightv be assumed that themetal hydrides function merely to react with catalyst poisons whichmight'be present in. small proportions of the order of Va few parts permillion in ethylene, propylene and/or in the liquid reaction medium; wehave found, however, that even extremely pure ethylene. or propylene andliquid reaction medium which have been contacted with alkali metal orwith calcium hydride under reaction conditions and directly thereaftercontacted in a separate zonewith molybdenum oxide catalysts, do notproduce solid polymer in the high yields or quality which can beattained by the process ot' the present invention.

We have further discovered that the claimed metal hydrides so activatemolybdena catalysts that we were enabled to obtain solid polymers bycontacting ethylene with M003 alone, i. e., without a support whichfunctions greatly to increase the surface area upon which M003 isextended.' Ethylene can beV converted to normally solid polymers bycontacting it with the hydride of a metal selected from the grouplconsisting of Be, Mg, Ca, Sr, Ba, and a group 6a metal trioxidecatalyst', provided the temperature is suiciently high to convert saidtrioxde, We prefer to employ' a partially pre-reduced group 6a metaltrioxide in our process. Prior to our invention, subhexavalentmolybdenum oxides were known to be catalysts for thepolymerization ofethylene to form normally-solid polymers only when supported upon thethree diflicultly reducible metal oxides: gamma-alumina, titania,zirconia. For the polymerization of ethylene and/or propylene to formnormally solid polymers in the presence of the claimed metal hydrides,the group 6a metal oxide catalysts can be extended not only' on alumina,titania or Zirconia, but also on other supports, e; g., silica gel,kieselguhr, diatomite; silica-alumina, aluminosilicates, such as variousclays and bleaching earths; and even adsorptive carbon, which is howevernot preferred. In a practical process, it is .preferable to furnish adiicultly reducible metal oxide support for the group 6st metal oxidecatalyst, e. g. gamma-alumina.

The proportion of metal hydride employed in our process can be variedfrom about 0.01 to about l or more parts by weight per part by weight ofgroup 6a metal oxide catalyst (total weight of solid catalyst), usuallybetween about 0.1 and about 1.0 parts by weight. The optimum proportionscan readily be determined in specific instances, by simple small-scaletests with the specific feed stocks, liquid reaction medium, reactionmedium: catalyst ratio, catalyst', temperature,'pressure and nature ofthe product which `is desired. Usually Cal-l2 is employed in proportionsbetween about 0.5 and about 2 parts by weight per part by weight ofmolybdena catalyst at ratios between about-5 and about 3000 volumes ormore,vof liquid reaction medium'per part by weight of molybdenacatalyst.

Another important advantage of the claimed metal hydrides, as comparedwith alkali metals and their hydrides, that they do not catalyze thealkylation of aromatic hydrocarbon reaction mediaby ethylene, propyleneor other monomers or unsaturated polymers. Furthermore, the claimedmetal hydrides do not catalyze' '4 colored polymeric 'materials' and aclear, white, solid product can be readily produced.

The relative proportions of support to the catalytic metal oxide is notcritical and may be varied throughout a relatively wide range such thateach component is present in amounts of at least approximately l weightpercent. The usual metal oxide support ratios are in the range' of about1:20 to 1:1, or approximately 1:10. We may employ conditionedalumina-metal oxide catalysts composed of gamma-alumina base containingabout l to preferably about. 5 to 35%, or approximately 10%, ofcatalyticrmetal oxide supported thereon.

Gamma-alumina, titania and zirconia supports for our catalysts may beprepared in any known manner and the oxides of molybdenum or other'group 6a metal may likewise be incorporated. in, or depositedon, thebase in any known manner, e. g. as described in copending Serial No.223,641 of Alex Zletz (now U. S. Patent.2,692,257) and Serial No.223,643 of Alan K. Roebuck and Alex Zletz (now U.S. Patent 2,692,258),both tiled on April 28, 1951. Excellent results have been obtainedy withmetal oxideV catalysts of the type conventionally employed for effectingcommercial hydroforming, the word hydroforming being, employed to meanprocessesl of the type described in United Statesk Letters .Patent2,320,147, 2,388,536,Y 2,357,332, etc. i

The molybdena or other molybdenum-oxygen compound, such as cobaltmolybdate, maybe incorporated in the catalyst base in any known manner,e. g. by impregnation, coprecipitation, co-gelling, and/ or absorption,and the catalyst base and/or finished catalyst may be heat stabilized inthe .known mannersl heretofore employed. in

the. preparation of hydroforming. or hydrofin'mg catalysts. Cobaltmolybdate catalysts may be prepared` as described in U. S. 2,393,288,2,486,361, etc. Cobalt, calcium, nickel and copper salts of chromic,`molybdic, tungstic and uranic acids may also be employed, with orwithout a support and are preferably treated. with hydrogen underconditions to effect. partial reduction before use in our process.

The catalyst may be stabilized with silicay (U. S. 2,437,532-3) or withaluminum ortho-phosphate (U. S. 2,440,236 and 2,441,297) or other knownstabilizers or lmodiiers., The catalyst. may contain calcium oxide (U.S. 2,422,172 and 2,447,043) or thebase may be in the form of a zincaluminate spinel (U. S. 2,447,016) and it' may contain appreciableamounts of zirconia or titania (U. S. 2,437,53l2,). Oxides of othermetals such as magnesium, nickel, zinc, chromium, vanadium, thorium,iron, etc., may be present in minor amounts, below l0 weight percentofthe total catalyst.

` Although, as statedy above,v no reducing treatment need be effected onthe metal oxide catalysts when they are employed in the presence of thealkaline earth metal hydrides, a reducing or conditioning treatment ispreferred in commercial processing. The conditioning or reducingtreatment of the hexavalent group 6a metal oxide is preferablyA eifectedwith hydrogen although'other reducing agents such as carbon monoxide,mixtures of hydrogen and carbon monoxide (water gas, synthesis gas,etc.), sulfur dioxide, hydrogen sulfide, dehydrogenatable hydrocarbons,etc., may be employed. Hydrogen can be employed as a reducing agentat'temperatures between about 350' C. and about 850' C., although it ismore often employed Vat temperatures within the range of 450 C. to 650C. The hydrogen partial pressure in the reduction or conditioningoperation may be varied from subatmospheric pressures, for example even0.1 pound (absolute) to relatively` high pressures up to 3000 p. s. i.g., or even more'. The simplest reducingV operation may beY effectedwith hydrogen simply at about atmospheric pressure. l

The partial reduction of the rnetal'oxide-catalyst in which the metalispresent in its hexavalent state can be effected in the presence of theclaimed metal hydride promoter, prior to contacting the combination ofcatalysts with ethylene. We have at times observed that an inductionperiod before ethylene polymerization can be eliminated or substantiallyreduced by pressuring hydrogen into the reactor containing the solvent,ethylene, metal oxide catalyst and metal hydride promoter, e. g. athydrogen pressures between about and about 900 p. s. i. g., preferably100-400 p. s. i. g.; under these conditions only a small proportion ofthe ethylene is reduced to ethane.

Lithium aluminum hydride, an exceptionally active reducing agent,conditions and activates catalysts containing hexavalent group 6a metaloxides even at temperatures as low as 35 C., although in generaltemperatures between about 100 and about 300 C. can be employed. Inpractice, a catalyst containing free or chemically combined group 6ametal trioxide is treated with a suspension of LiAlH4 in a liquidhydrocarbon at weight ratios of about 0.2 to about l LiAlH4 to solidcatalyst. Sodium hydride (or sodium plus H2) is effective in reducingand conditioning hexavalent molybdenum trioxide or other group 6atrioxide catalysts at temperatures above about 180 C. and may beemployed in the same proportions as LiAlHr. Calcium hydride effects somereduction of MoOa supported on gamma-alumina at temperatures of 265 C.and higher temperatures.

The conditioning and reducing treatment of the group 6a metal oxide canbe followed and controlled by analysis with ceric sulfate-sulfuric acidsolution, by means of which the average valence state of the molybdenumor other metal oxide in the catalyst can be accurately determined. Indetermining the average valence state of metals such as molybdenum incatalysts such as partially reduced M003 supported on diicultlyreducible metal oxides such as gamma-alumina, it is necessary to knowthe total molybdenum content and the number of milliequivalents of astandard oxidation reagent required to reoxidize the partially reducedmolybdena to M003. A suitable oxidation procedure consists in weighingout approximately one gram of finely-ground, freshly-reduced catalystinto a glass-stoppered Z50-ml. Erlenmeyer flask and adding ml. of 0.1 Nceric sulfate solution and 25 ml. of 1:1 sulfuric acid. This mixture isallowed to stand at room temperature for four days with frequentagitation. This interval was abritrarily chosen initially but was latershown to be more than sufficient time for the oxidation to take place.The solid residue is then ltered off and the excess ceric solutiondetermined by addition of excess standard ferrous solution which is inturn titrated with standard ceric solution usingferrous-orthophenanthroline as the indicator. Total molybdenum in thesample is determined by dissolving the sample in a sulfuricacid-phosphoric acid solution, reducing the molybdenum in a Jonesreductor, catching the reduced solution in ferric alum, and titratingthe resulting ferrous ion with standard ceric sulfate solution. From thevalues obtained, the oxidation state of molybdenum can be determined.

The partial reduction of the molybdena or other group 6a metal trioxideis carried out to the extent that the average valence state of thecatalytic metal in the catalyst lies within the range of about 2 toabout 5.5, preferably between about 3 and about 5.

The conditioning treatment hereinabove described is desirable not onlyfor fresh catalyst, but is also required for catalyst which has becomerelatively inactive in the polymerization step. As will be hereinafterdescribed, the polymer formed in the polymerization reaction must becontinuously or intermittently removed from the catalyst particles,preferably by means of solvents, and it is usually necessary ordesirable to condition a catalyst surface which has been thus freed tosome extent from polymer before it is again employed for effectingpolymerization. When catalyst can no longer be rendered suticientlyactive by simple removal of polymer and conditioning with a reducing gasas hereinabove described, it may be regenerated by extraction withwater, ammonium salts or dilute aqueous acids, thereafter burningcombustible deposits therefrom with oxygen followed by the conditioningstep. Detoxification of the catalysts by treatment with dilute aqueoussolutions of per-acids such as permolybdic, pervanadic or pertungsticacids may be practiced, followed by hydrogen-conditioning of thecatalysts.

The catalyst can be employed in various forms and sizes, e. g., aspowder granules, microspheres, broken lter cake, lumps, or shapedpellets. A convenient form in which the catalysts may be employed is asgranules of about 20-100 mesh/inch size range.

The charging stock to the present polymerization process preferablycomprises essentially ethylene. The ethylene charging stocks may containinert hydrocarbons, as in refinery gas streams, for example, methane,ethane, propane, etc. However, it is preferred to employ as pure andconcentrated ethylene charging stocks as it is possible to obtain. Whenthe charging stock contains propylene as well as ethylene, both theseoleiins may contribute to the production of resinous high molecularweight products. The molar ratio of ethylene to propylene may be variedover the range of about 0.1 to about 20. The charging stock may containother components such as small amounts of hydrogen and it may containother polymerizable materials such as butylene, acetylene,tbutylethylene, etc.

It is desirable to minimize or avoid the introduction of oxygen, carbondioxide, water or sulfur compounds into contact with the catalyst.

In general, polymerization can be effected in the present process attemperatures between about 75 and about 325 C. Increasing thepolymerization temperature tends to reduce the average molecular weightand density of the polymer produced by the process. Usuallypolymerization is effected in the present process at temperaturesbetween about 110 and about 275 C. or the preferred narrower range ofabout 220 to about 260 C. The conjoint use of polymerizationtemperatures between about 230 and about 260 C. and a liquid hydrocarbonreaction medium such as benzene, xylenes, decalin, or methyl decalins ishighly desirable in producing ethylene polymers having specificviscosities (X) ranging on the average from about 10,000 to about 30,000in continuous operations with relatively long on-stream periods andactive catalysts.

It has been found that the present process can be employed for theproduction of relatively high molecular weight ethylene or propyleneheteroand homo-polymers at relatively low pressures. The process of thepresent invention can be effected to some extent even at atmosphericpressure. The upper limit of polymerization pressure is dictated byeconomic considerations and equipment limitations and may be 10,000 p.s. i. g., 20,000 p. s. i. g., or even more. A generally useful andeconomically desirable polymerization pressure range is between about200 and about 5000 p. s. i. g., preferably between about 500 and about1500 p. s. i. g., e. g. about 1000 p. s. i. g.

The Contact time or space velocity employed in the polymerizationprocess will be selected with reference to the other process variables,catalysts, the specific type of product desired and the extent ofethylene conversion desired in any given run or pass over the catalyst.In general, this variable is readily adjustable to obtain the desiredresults. in operations in which the olefin charging stock is caused toflow continuously into and out of contact with the solid catalyst,suitable liquid hourly space velocities are usually selected betweenabout 0.1 and about l0 volumes, preferably about 0.5 to 5 or about 2volumes of olen solution in a liquid reaction medium, which is usuallyan aromatic hydrocarbon such as benzene, xylenes, or tetralin, or acycloaliphatic hydrocarbon, such as decalin (decahydronaphthalene).x

The amount of ethylene or propylene in suh solution may be in the rangeof about 2 to 50% by weight, preferably about 2 to about l0 weightpercent o'r, for exam-- metal oxide catalysts.

'polymerization reaction it is then possible to treat the ple, about 5`to l0 weight percent. We have observed that when 4the ethyleneconcentration in the liquid reaction medium is decreased below about 2'weight percent, the molecular weight and melt viscosity 'of thepolymeric products drop sharply. The rate of ethylene polymerizationtends to increase with increasing concentration Vof the ethylene in theliquid reaction medium. However, the rate of ethylene polymerization. toform high molecular weight, normally solid polymers isqpreferably notsuch as to yield said solid polymers in quantities which substantiallyexceed the solubility thereof in said liquid reaction medium under thereaction conditions, usually up to about 5-,7 weight percent, exclusiveof the amounts of polymeric products which are selectively adsorbed bythe catayst. Atlhough ethylene concentrations above l weight percent inthe liquid. reaction medium may be used, solutions of ethylene polymerabove 546% in the reaction medium become very viscous and difficult tohandle and severe cracking or spelling of the solid metal oxide catalystparticles or fragment may occur, resulting in' catalyst carry-over asfines with the solution of polymerization' productsv and etxensive lossof catalyst from the reactor.

In batch operations, operating periods of between onehalf and about l()hours, usually between about l and about 4 hours, are employed and thereaction autoclave is charged with ethylene as the pressure falls as aresult of the Volen conversion reaction.

The solventzcatalyst weight ratio can be varied in the n range of about5 to about 3G00, or even higher for ilow systems.. The employment ofhigh solvent:catalyst ratios, which is rendered possible by the presenceof one or more of the hydrides of Be, Mg, Ca, Sr and Ba in the reactionzone, is' very/'important in` obtaining high yields of polymer.

The olefin charging stocks can be polymerized in the gas phase and inthe absence of a liquid reaction medium by contact with the claimedmetal hydrides and group 6a Upon completion of the desired solidcatalyst for the recovery of the solid polymerization products, forexample by extraction with suitable solvents. However, in the interestsof obtaining increased rates of' olen conversion 'and of continuouslyremoving solid conversion products from the catalyst, itv is muchpreferred to effect the conversion of the olen in the presence Vofsuitable liquid reaction media. The liquid reaction medium may also beemployed as a means of contacting the oleiu with catalyst by preparing asolution of i the olcn iced stock in the liquid reaction medium andcontacting the resultant solution with the polymerization catalyst. n

The liquidl reaction medium functions as a solvent to remove some of thcnormally solid prodrmt'V from the catalyst surface.

Various classes of hydrocarbons or their mixtures which are liquid andsubstantially inert under the polymerization conditions of the presentprocess can be employed.

- Members of the aromatic hydrocarbon series, particularlythemononuclear aromatic hydrocarbons, viz., benzene, toluene, xylenes,mesitylene and xylene-p-cymenc mixtures can be employed.Tetrahydronaphthalene can also be employed. in addition, we may employsuch aromatic hydrocarbons as ethylbenzene, isopropylbenzene,sec-butylbenezne, t-butylbenezne, ethyltoluene, ethylxylenes,hemime-llitene, pseudocumene, prehnitene, isodurene, diethylbenzenes,lisoamylbenzene and the like.

kare liquid under the polymerization reaction conditions,

for example, l-methylnaphthalene, bisopropylnaphtha-V lene,I-n-amylnaphthalene and the like, or commercially produced fractions`containing these hydrocarbons.

Certain classes of' aliphatic hydrocarbons can also be employed as aliquidhydrocarbon reaction medium in the present process. Thus, we mayemploy various saturated hydrocarbons (alkanes and cycloalkanes) whichare liquid under the polymerization reaction conditions and whichV donot crack substantiallyA under the reaction conditions. Either purealkanes or cycloalltanes or commercially available mixtures, freed ofcatalyst poisons, may be employed. For example, we may employ straightrun naphthas or kerosenes containing alkanes' and cycloalkanes.Specifically, we may employ liquid or liquefied alkanes suchrasn-pentane, n-hexane, 2,3-dimethylbutane, n-octane, iso-octane(2,2,4-trimethyipentane), n-decane, n-dodecane, cyCIOheXane,methylcyclohexane, dimethylcyclopentane, ethylcyclohexane, ldecalin,Amethyldecalins, dimethyldecalins and the like.

We may alsoemploy a liquid hydrocarbon reaction medium comprising liquidolefins, e. g., n-hexenes, cyclohexene, octenes, hexade'cenes and thelike.,

The normally solid' polymerization products'which are retained on thecatalyst surface or grease-like ethylene polymers may themselvesfunction to some extent as a liquefied hydrocarbon reaction medium, butit is highly desirable to add a viscosity-reducing hydrocarbon, such asthose mentioned above, theretoin the reaction zone.

The liquid hydrocarbon reaction medium should be freed of poisons beforeuse in the present invention by acid treatment, e. g., with anhydrousp-toluenesultonic acid, sulfuric acid, or by equivalent treatments, forexample with aluminum halides, or other Friedel-Crafts catalysts,maleicanhydride, calcium, calcium hydride, sodium or other alali metals,alkali metal hydrides, lithium aluminum hydride, hydrogen andhydrogenation catalystsV (hydroining) ltration through a column ofcopper grains or 8th group metal, etc., or by combinations ot suchtreatments.

We have purifiedA C.y P. Xylenes by reluxing with a mixture 'ofMODs-A1203 catalyst and LiAlH4 (50 cc.

i xylene-l g. catalyst-0.2 g. LiAlHi)V at atmospheric llt pressure,followed by distillation of the xylenes. Still more effectivepurification of solvent can be achieved by heating it to about 225 -'250C. with either sodium and hydrogen or NaHy in a pressure vessel.

Temperature control during the courseV of the ethylene conversionprocess can be readily accomplished owing to the presence in Vthereaction zone of a large liquid mass having relatively high heatcapacity. The liquid hydrocarbon reaction medium can be cooled by heatexchange inside or outside the reaction zone.

When solvents such-as xylenes are employed some slight alkylationthereof by ethylene can occur under the reaction conditions. Propyl'eneis `a far more reactive alkylating agentA than ethylene and whenpropylene is present in the feed, it is desirable to employ anonalkylatable lsolvent such as decalin. The alkylate is removed withgrease in the present process, can be separated therefrom by fractionaldistillation and can', if desired, be returned to the polymerizationzone.

An illustrativeow diagram indicating one methodl by which the process ofour invention may be eiected is set forth in the accompanying figure.The olenic charging stock, e. g., ethylenel or an ethylene-propylenemixture, is passed through compressor 10 wherein the pressure thereof israised toV a suitable value, for example, between about 500 and 2000pounds, thence into chamber 11, which is provided with a suitabledeoxygenating agent such as metallic copper at C., then into chamber' 12which is'provided with a dehydra'tng agent such as adsorptivealumina,anhydrous calcium sulfate, silica gel o1' equivalent drying reagent. Thedried charging stock is passed from chamber lz-ntochamber 13 whereincarbon dioxide is removed from the charging stock. Chamber 13 isprovided with a suitabley reagent,V for example,

valved line 16 and heat exchanger 17, wherein it is brought toa suitabletemperature forabsorpton, usually between about and about 35 1C.although higher or lower temperatures can be used; recycle solvent fromline 61 may also be charged to the absorber or may be the sole`absorption medium employed. In absorber 14 a solution containing betweenaboutZ and about 30 percent olefin, e. g. about? weight percentethylene, is` produced and is withdrawn through valved line 18 into aguard chamber 19 for final purification. The guard chamber may containan active metal or metal hydride, for example, sodium or otheralkalimetal,` an alkaline earth metal, an alkali metal hydride or an alkalineearth metal hydride. The guard chamber lmay be iilled with cal'- ciumhydride. The guard chamber may be operated at temperatures between about100 and about 280 C. If the feed stock is of sufficient purity, theguard chamber may be by-passed (by lines not shown) and introduceddirectly into reactor 25.` u j u From guard chamber 19 the ethylene andsolvent are discharged into line 20, thence through pump `21 into heater22 wherein they are brought to the polymerization temperature, forexample, between about`200 and about 275 C.` From heater 22`the chargeis passed through line 23, thence through line 24 into the lower end ofreaction chamber 25. While a` variety of suitable reactors can beemployed, in the accompanying figure there `is illustrated an autoclavedivided into upper and lower sectionsby baiiie 26. A stirring mechanism`27 projects into the lower portion of the reactor` and suitable baies28 are provided at the walls. The stirring mechanism may be operated atabout to about 1000 R.`P. M., e. g., about 650 R. P. M. It will `beapparent, therefore, that a high degree of intermixing between thecatalyst, metal hydride, oletinic material and liquid reaction medium isachieved in the lower portion of reactor 25. Reactor may be initiallycharged with the group 6a metal oxide catalyst and metal hydride throughlock hopper devices or equivalents, and further amounts of metal oxidecat alyst and metal hydride can be added intermittently during thecourse of the reaction, means.

sIf desired, a portion of the predxied solvent can be passed throughvalved line `29 and heater 30, wherein it it brought to a temperaturebetween about 150 and about 300 C., into a contacting chamber 31provided as desired, by suitable with baille 32, stirring mechanism 33andan inlet 34.for; metal hydride. An intimate dispersion of metalhydride in solvent is formed in contactor 31 and is withdrawn from theupper quiescent zone of contactor 31 through valved line 35 into line24, and is forced by pump 36 into reactor 25. An alternative and veryuseful method of purifying the solvent in contacting chamber 31` is totreat said solvent with an alkali metal hydride, usually NaH, and asupported group 6d metal oxide, e. g. 10

weight precent MoOs-gamma alumina, using about 3 to about 10 parts by`weight of u supported metal oxide `per partby weight of alkali metalhydride, at a temperature between about 135 and about 270 C. and liquidspace velocities between` about 0.5 and about 10.

In reactor 25, the polymerization' of ethylene or propyl V ene orcopolymerization of ethylene with other polymeric materials, is electedat suitable temperatures and pressures. The usual concentration fotlethylene in the solvent entering the reactor is about' 10w`eight percentand the efuent from the reactor" is usually a` 2-5 weight percentsolution of solid polymer in the solvent.` When the hourly u preparationof a homopolymer of ethylene having a Staudinger speciic viscosity (X)of about 15,000 to 30,000, melt viscosity of 2 05 to about 5 106 poisesis desired, the preferred temperatures are between about 230 C. andabout 275 C. The reaction period can be varied between about 10 andabout 100 minutes.

It will be understood that instead of one reactor we may employ a numberof reactors in parallel or in series. When reactors are employed inseries, variations in temperature and pressure, olefin concentration insolvent, and catalyst concentration become possible so that more controlcan be exerted over the average molecular weight and molecular weightrange of the product, as well as of the extent of conversion in eachstage. Also, through the employment of a number of manifold reactors,suit` able by-pass lines and valves, it becomes possible to cut any`reactor out of the system for purposes of cleaning and repair. q

The upper portion of reactor 25 constitutes a quiescent settling zonewherein iine catalyst particles and (nonradioactive group 2a) metalhydride settle from the solution of polymer product in the reactionsolvent and return under the force of gravity to the lower agitatedportion of the reactor. The relatively clear solution of reaction.products in solvent is withdrawn from the upper portion of reactor 25through line 37 and expansion valve 38, wherein the pressure is allowedto fall to a value between about l5 and about 250 p, s. i. g. Theproduct mixture discharged from valve 38 tangentially into a separator,e. g., a cyclone-type separator 39 wherein a temperature of at leastabout C. is maintained. Gas comprising a substantial proportion ofethylene in a poison-free condition is discharged from separator 39through valved line 40. Hot solvent may be introduced intoseparator 39through line 51 in order to prevent separation of polymer upon thewallsof the separator. The solution of polymer in solvent (maximum ofabout 5 weight percent polymer) is withdrawn from separator 39 throughvalved line 41, into filter 42, wherein any tine catalyst particleswhich may have been carried along, are separated and withdrawn throughvalved line 43. If desired, the polymer solution may be subjected to theaction of ultrasonic vibrators, which eiect coagulation of the very tinecatalyst particles so that they can be more readily filtered.

The solution of polymer product is withdrawn from filter 42 through line44 into cooler 45, wherein its temperature is adjusted to a valuebetween about 90 and about 20" C. and is then discharged through line 46into iilter 47. The solid polymer product is removed from filter 47 at48 and the solvent or reaction medium is withdrawn through line 49,whence a portion can be discharged from the system through valved line50, a portion can be passed through valved line 51, pump 52 and heater53 into separator 39, and the remainder can be passed through valvedline 54 into fractionator 55. Y

Precipitation of the polymer from the solution in line 44 can be inducedby the addition of antisolvents such as low boiling alcohols, ketones(acetone), etc. The polymeric product of the present process removed ati3 can be subjected to various treatments to prepare it for conversionto a finished industrial product. Thus, it may be subjected to varioustreatments to remove the imbibed solvent, it may be shredded or extrudedto form stringlike particles, dried, etc.

l In fractionator 55, the solvent or liquid reaction medi um isvaporized and passes overhead through line 56, whence a portion mayberemoved from the system through valved line 57, but is preferably passedthrough 4valved line 58 into cooler 59 wherein its temperature isbrought Vto a value between about 20 and about 80 C., whence it ispassed into pump 60. Pump 60 forces the solvent through valvedline 6land heat exchanger 17 `into absorber 14 to` prepare a solution of fresholeu charging stock for the polymerization process. A porthoroughlydried inconventional equipment;

smeation of Ythe solvent is also forced by. pump 60 through valved linewinto theV upper portion of absorber; 63;. Recycled gases from separator9:andline1407^ are passedi throughfval'ved line 65f and compressor' 65lthrough line;Y 66' into 'thelower portion ofabsorber. 63; inwhich'olefin iseseleetivel'y absorbed; ini the solvent' to produce a: solutionhavinga-'concentration' between` about 2" and. about l'O'4 weightpercent'A of ethylene',l which isdischarged from absorber-63 throughvalvedline'Tinto lin-e 20; whence; it ispassed to reactr25.Ur'labsorbed'v gases areV dischargedj from -absorber' 63 through valverllinel 68.

' Liquidreaction products boiling above the boilingrange` of' thesolventl medium'can' be Ydischarged from fraction"- atory 55ev and the'process through valvedline` 69'but` are preferably j passed` throughval'vcdl line. 70` into a' second.

fractionator4 71. A byproductjofthepresentpolymeriiaf tionprocessifproduced in` rclativelysmall: volumel when an'- alleylatable'varomatic hydrocarbon solvent such as a xylene is employed, is analkylate formed by reaction of' said alkylatablearomatic hydrocarbon`and ethylene (orfpropylene', when itfisA employedl as'a' componentiofthech'argingstock); The allylated aromatic hydrocar-l bon products f arefvapori'zedf and fractionated"` in' tower 71, from` which theyare'-dischargedthrough line 72; ltis usually desirable' to recycle at'least; a portionof" the al'-v ltylate' through val'vcdfline 73: toline"4l'forernployment -V as adiluent-l and solvent in fl'terr42 Theremainder-of the'alkylate may be discharged fromA the. process throughvalved' line 74 or mayf be recycled forl employment' asr` part of' theliquid reaction medium iir reactor" 25" Relatively-'small proportionsoflow molecularweight' grease-like olefin polymers areA produced in thelpoly-'- merization process. The greasedike products'- are re moved" asay bottoms' fraction from tower 71 throughv valved line 75':

fwater andI steaml at a temperature sufficient to' flash distil thesolvent (or `anazeotropel of solyentiand' water) fronrthe solution and`to produceA a water slurry ofc the.

solid'polyrner containing about 1' to about 5 Weight.'

percentfpolymer. The aqueous slurryv of'A p olymercan be concentrated.by conventional methods toA yield. aV

slurry' containing aboutv 10 to l5/weightgpercent polymen. which canthereafter be centrifuged to yield a polymer containing' a minorproportionV of Wate1,.whichv can be..

vventpassing overhead`in.the ash distillation operation. can becondensed, separated fromk a lower liquidllayer of water, redistilled tofurther. dry it `and finally can be thoroughly dried with desicca'nts,e. g. silica gelor alu-V mina gel, prior to'recycle to. storageorv tothe polymerizaa gammaalumina, The' molybdena. catalyst waspre-reducedunless` otherwise indicated; Standardized' pre-rev- Theisol-l action' vesselIk after thelatter' had been heated, to thereactionA temperature: 'l'hejmagnetically' driven stirrup# type..stii'rerrl was alternately lifted and plungedV down through the"solution at a ratesucient` to keepthe cata- 'lystiinesuspensioni Theoletn feed was Yintroduced from timetdtiine during thevk course ofth'evrun in order to maintainsthereacti'on pressure. A minor hydrogen par.-tial-pressure,oiitliejorderofi about 10G-200 p; s. i. g;

may; bet'superirnposed on .the oleirpressure; when' thek reactionfails?. to. start readilyi.' Byjplotting cumulative pressure di'opjagainst cumulatiye i time; the progressv off a" runcanbej followed. Ihmanycas'e's much higher yields might* have been` obtained; had`provision' been" marieV fr'theinclusion of a largerprozgortion'ofsolvent' in reaction zane since; one ofthe'V reasons' for' run ter`minatic'nrV was jamming of the stirringV mechanism duet to" the-'facuthat theV high molecular weight polymerjwas' produced" in the reactionzonein angam'ount exceeding;

t its solubility in the liquid reaction` medium under the` i.prornotefrs1v willi] hel appreciated. by;y bearing the following'Vinformation in* mind: In a run carried out' employing.

' mesh powder ofS Weight percentj MoOs'supportedl onvr duction ofl themolybdena catalyst was carried' out with diy' hydrogen passing atatmospheric pressure through. the. catalyst at approximately 5 litersper hour per ll0 grams ofgcatalyst. for 16K hours at Y480C., althoughother temperatures were. also used, as indicated.` in the table.

The reactions'fwerecarried' out in .pressure vessels hav-1 reaction.conditions; Y

The-.important effects. ofL our alkaline earth hydride the general"operating procedure; above4 descrihed;V errrploying the 8. weightpercent pre=reduced molybdenagamma-alumina catalyst and Ya4 C; P.xylenes'rcatalyst p: s; 'if g..initial ethylene0 pressure, ethylenebeing, rel.

pressured'into the;reactoruntil no further: amount' could be absorbed.

The results" of` examples are" usually self-evident;

however; some" comment" willv be lfurnished hereinafter. toi

interpret theresults; In Examples` 1l` and"2..1nolybdena alone was'employed as' the catalyst: Ylt will' be` noted'A the' calcium`Ahydride.exertedsuieient promoting action to' effect .theproductionlofrahout" 1 gram" ofv polyethylene portionU oflcalcium"hydride`was'lessg' the yield"'ofpolyr ethylene wassomewhat'reducedalthough the productfhad"kl a higherspecihc viscosity. Acomparison offEXarnples 3 and`4.. indicates that' even mildprereductionof` a* molyhdena-aiumina: catalyst" tends.'l to produce a substantial'increase' in the" yieldoy polyethylene' and?V as wev havefoundjmoref'oftena desirable prod ilretgi;v e: one having a suitableVspecific; yi'scosity?l Howeverg.. as shown. by Ex-y ample' 5;; andmuclr'morestrikingly'hy "Example 8, a com-- Y merciallypractical;yield`vr of" solidI Vpolyethylene havingV a suitablespecic'fviscositycam be prepared by the'conjoint employmentofa calcium' hydride catalystand a calcined,l supportedmolybdenahgammaralumina Y Yj Vry'rhigll;but".not"'limit`ing, yi lds ofnormally solid polyethylene wereV obtainedAin the series of. Examples .7` to` 14; inclusive.'k Inl general,itfmay. be 'saidJ that the'emple 9'; in which, wel emplyedf extremelypure. ethylene.l

(deoxygenated,.deearbonated.alddehydrated). and xylene pressure.ve.ssel,. the yextremely 'highs yield of.- 1179. grams.

' per. gram`v offsolidI polyethylenegcapable of forming a tough..andfrllexible;fi1m,ws obtainedl In..Exampl-9 fixEimple. 10T a.;verydesirahle l.yield of commercially. Y

suitable solid polyethylene was obtained when the molybpressure of 5300p. s. i. g. and the relatively high teiilH dena catalyst was pre-reducedat the extremely high temperatures of 270-290 C.

perature of 700 C. A comparison is afforded with Ex- Brief discussionwill now be devoted 'to some examples ample 1l wherein a much lowerpre-reduction temperain which the most important variation was thesolvent ture was employed, with desirable effects both upon the 5 whichwas employed. In Example 8, the benzene solvent yield of normally solidpolyethylene and the properties of was purified by heating with calciumhydride at 260 C. the product. It will be noted that similar results tothose and the ethylene was, likewise, purified, resulting in a obtainedin Example l1 were obtained in Example 12. very high yield of solidpolyethylene having the extreme- Table Yield of iox diilced MH P SOL PSlolid S102i;i hxfgelt Density y i ressuro, oymer pee c so ExampleCatalyst, g.1 H g" f T C. p. s* i. g., vent, g'lg.. of 1 Vw cosity Film7 Solid Remarks at Solid cosity Poises 6 Poly T Op Catalyst mei- 0. 5280 1, 000/170 60X 1. 03 12. 5 4 9. 3 TF 9, 623 CHt/CHa=40.

1. 275 1,0 50X 0. 52 30 6 1.05 TF 9, 596

0. 262-296 900/150 100X l. 14 5. 5 Low 9, 800

0. 5 232 S60/140 3. 9 53. 6 7 2. 4 TF 9, 601

0.5 255 940/110 50X 6.18 39.3 0 6.2 TF 9,588 Caleinetcl1 cattlyst; not

re-re uee 0. 255 895/120 lOOX 21. 8 17. 5 5 2. 8 TF 9, 632 Vy purereagents.

0` 5 256 S40/160 100X 52. 4 23. 9 6 2. 95 TF 9, 637 Do.

0. 1 230 1,000 50B 51.9 55 7 2. 1 TF 9,700 Benzene and ethylenespecially purified by heating vwith CoH, at 260 G. Catalyst notpre-reduced.

0 5 256 5/135 100K 179 22. 7 3. 7 TF 9, 627

0 5 255 870/110 100K 19. 4 41.1 7 1.2 TF 9, 588

0 6 256 870/110 100K 26. 6 24. 2 3. 4 TF 9, 624

0 5 255 S40/140 100X 29.5 32.9 67 TF 9,601

0 5 255 S50/130 100X 24. 2 30.1 4. 6 TF 9, 592

0 5 256 1,020 100X 16 17. 9 5 9. 2 TF 9,664 Catalyst not calcined.

2 270-290 5, 300 50D 0. 22 50 TF 9, 695 High ptressure and temera uro.

0 5 275 975/70 50D 6 14 5 53. 45 TF 9,663 p 200 580 50S 1.09 S t is2-methyl-2-buene.

1 0 229 865 50S 1.85 l 6. 5 9, 569 S is 2-ethylhexerie.

2 250 S40/900 100D 1- 8 H2 is added after poly merlzation.

0 5 230 Q30/00 50X 2.8 71 73 9 TF 9, 554 20% SiOz added to catalyst asthird component.

1 255 87o 100x s. 47 21. 5 e 1 TF 9, 679

1 i 255 900 100x 7.8 28. 2 2.4 TF e 672 1.0 0. 5 326 915/135 100D g(()rzOa-69 A1203. 375 2 230 850 100X 26 l'wggzlj'z: 445 2. 0 253 800100X 27 450 1.0 203 835 50S 2.24 32.7 7 TF 9 364 Isooctane solvent; 5WO2`ZrO"-" y ce. propylene added during run. 28 9 5.0 1.0 156 500 50D0.28 Soft, tacky, elastic polymer. 29s 5 2.0 155 500 50S 0.4 Swascyclohexane. 30 8 5 2. 5 155-200 800/1, 000 30D 0. 5 D percolatedthrough 1S'iOi to remove tetrain. 31B 5CoM0O4 480 2 200 1,000 50D 0.3 321.0 0. 5 230 920/100 45X 2. 9 87. 5 7 6. 9 TF 9, 585 5 ce.y3-ethyl2pentene 5 0 y Y added during tun. e3 {2.177.' 'Ee''' 375 2.o 23a250 100x 0.36 1 4.4 9, 551

Choa-A1202. BaHz 1 Unless otherwise indicated, the catalyst was 8 W.percent MoOa-gamma alumina, usually 20-85 mesh, pre-reduced withhydrogen at 480 C. and 16 hours at 1 atm. and 5 l. per hour of Hi.

2 C2H2 unless otherwise indicated. i

3 When two pressures are shown, the upper figure is the initial olefinpartial pressure and the lower figure is the initial hydrogen partialpressure. 4 X means xylenes; B means benzene; D means decalin; S meansspecial solvent, identified inthe Remarks column. 5 The specificviscosity is (relative viscosity 1) and relative viscosity is the ratioof the time ot etliux oi a solution of 0.125 g. polymer in 100 cc. C. P.xylenes at 110 C. from the viscosimeter as compared with the time ofetllux of 100 ec. C. P. xylenes at; V110" C. b hAs determined by themethod of Dienes and Klemm, J. Appl. Phys. 17, 458-71 (1946). Thesuper-script refers to the exponent of 10 times the numer given.

7 T means tough; F means flexible; B means brittle; S1. means slightly.8 Propylene polymerization.

wherein an intermediate pre-reduction temperature was ly high specieviscosity (X105) of 55,000. The polyemployed. 35 ethylene was alsocharacterized by high density and its In Example 14, the catalyst wasemployed in the form capacity Vto form a tough, iiexible lm. Decalinproved of a 30-100 mesh filter cake which had not been calcined to be asatisfactory liquid reaction medium for ethylene at all. Nevertheless, asurprisingly high yield of good polymerization, as will be noted fromthe results of Exquality polyethylene was obtained, as will be notedfrom ample 16. Decalin has also been used in various other the table,and the product quality was commercially deexamples, as will be notedfrom the table.

sirable. The yield, in fact, might have been considerably In Example 17,the solvent was Z-methyI-Z-butene. greater had not the accumulation ofsolid polyethylene in No doubt, the `yield of solid polyethylene couldhave been the reactor caused the stirring mechanism to jam,forcsubstantially increased by careful exploration of the reing thediscontinuance of the run. action conditions to determine those whichare optimum. In Example 1 5 a solid polyethylene of high specific 75 Thesame may be said of Example'lS wherein the solvent viscosity wasproduced by operating a partial ethylene was Z-ethylhexene. Y'

. function vto polymerize ethylene to solid polymers.

Y' and 25 Vgrams `of calcium'hydride.

overl a period of 9'hours at245 C. and ethylene partial Example 19 isofinterestin that the solid polyethylene was treated with hydrogen tosaturate it.

Brief consideration will be given .at thisrpoiut tocertain examples inwhich the important variation was in the support employed ffor themolybdenum oxide catalyst component. In Example20, 2O weightpercentsilica was added to the '8 weight percent molybdenafgamma-aluminacatalyst. It willlbe notedthata fairlygood yield o'fpolyethylene wasobtained,"having an extremely high specific viscosity. In Example 21, an8 weight percent molybdena-ou-silica catalyst was employed to produce adesirable yield of solid polyethylene having desirable commercialproperties. Similar results were obtainedinfExample 22 wherein 8 weightpercent molybdenasupported on Attapulgus clay was employed. When a.hydride promotor is not employed, molybdena-silica catalysts caninot InExample .23, unsupported calciumniolybdate, pre-reduced with hydrogen at350 ,C. wasthe catalyst. Althoughno attempt was made to dene the optimumoper-atingconditions in Example,23,it will be notednonetheless, that asubstantial :yieldof solidjpolyethylene was produced.

.In Example24successful results were obtained at'therelativelyhigh-reaction temperature of 326 C.

AExamples'of group 6d metal oxides other than molybdena are.25 and .26,wherein supported chromia and tungstia catalysts were respectivelyemployed.

In Example 27 ethylene'was polymerized over a tungstia-zirconia catalystin the presence of an isooctane solvent and 5 cc. .of `liquid propylenewere added over the course kof the mn to copolymerize with the ethylene.A commercially attractive-polymer of relatively high specific viscosityand relatively low density was produced,which was capable of beingmolded into a tough, ilexibleffilm.

VThe polymerization of propylene over the catalysts of thepresentvinvention proceeds'at a substantially lower Tate than thepolymerization oi ethylene, as will be noted from the data set forth inExamples 28, 29, 30, vand 3l. The propylene polymer produced inExample'28 was 4a soft, tacky, elastic solid.

InY Example 32 a product of extremely high specic viscosity was obtainedby vintroducing 5 cc. of liquid 3- ethyl-2pentene into :the reactor toco-react with the ethylene andto yielda polymer capableofbeingtformedinto avery tough, ilexible. film.

In `Example 33, a chromia-alumina catalyst wasemployed, promoted by.barium hydride.

yAlthough the tabulated examplesinvolve batch operations, the-inventionhas been successfully practiced in continuous ow operations, asillustrated by the `following example.

Example 34 charging stock was carefully puriiied toremove oxygen,

carbon dioxide and water and was prepared for reaction as a l weightpercent solution'in'highlypuri'iied xylenes. The ethylene solutioninxylenes was passed throughga guard chamber containing calcium hydrideaud-was then passed into the reactor containing 63 grams of 8 percentmolybdena-gamma-alumina catalyst (pre-reduced with dry hydrogen at 480C., atmospheric pressure, 16 hours, at therate-of liters of hydrogen peryl-l() g. of catalyst) The run was effected pressure lof 10001:. s. i,g., resulting in overall :ethylene conversion of 57 weight percent. Atotal of 35,4 grams of ethylene was pumped vthrough the Yreactor and97.6

weight percentof the `ethylene was accounted forduring the run. AIt wasvfound that normallysolid ethylenepolymer was being producedattheaverage rate of 0.24 gram per .gramof ucatalyst ,perhoun Theproductdistribution was `,8.6.1 weight .percent ofethylene being converted tonormally `solid .polymer, 12.6 `weight vpercent .to greaselike polymer,and 1.3 weight percent to a xylenes alkylate.

.1e Themelt -yiscosity .of .the V,solid lethylene polymer was2X'1f0'5poises.

.We .may employ group .5a metal oxide catalysts in lieu of Vthe group 6ametal oxides in our process, viz., oxides of vanadium, columbium .andtantalum, the process remaining `otherwise unchanged in all Vessentialregards. The vvariant process employing said group 5a metal oxidecatalysts `is describedand claimed `in our application `for UnitedStates 'Letters Patent,-Serial No. 369,723, filed vJuly 22, 1953.

The polymers produced by the process of this invention can be subjectedto such afterLtreatment as may be desired, to fit them for particularuses or to impart desired properties. Thus, the polymers can lbeextruded, mechanically milled, lmed o r cast, or yconverted to Spongesor latices. Antioxidants, stabilizers, fillers, extenders, plasticizers,pigments, insecticidesgfungicides, etc. can be incorporated in thepolyethylenes and'/ or in by-product alkylates or "greasesf Thepolyethylenes may be employedas coating-,materials binders, etc. to:even a wider extent Vthan vtween about .0l and about l percentfof thevarious polymers of ethylene produced by the process of the presentlinvention can be dissolved or dispersed in hydrocarbon lubricating oilsto increase V. I. and to decrease oil consumption when -the compoundedoils are employed in motors; larger amounts of polyethylenes may beVcom- I.pounded with oils of various kinds and for various purposes. v

The products having amolecular weiglit'of 50,000 or more producedby thepresent invention, can be employed fin small proportions tosubstantially increase the viscosity 'of uent liquidhydrocarbon oils andas gelling agents for suchoils. Thesolution of about 1 gram of anethylene polymer produced by this invention, having a specific`viscosity X of about 50,000 in about one liter of xylenes at atemperature close to the boiling point, produced an `extremely viscoussolution.

The polymers produced by the present process can be Vsubjected tochemical modifying treatments,.such.as haloygenation,halogenationfollowed by dehalogenatiomsulfohalogenation by treatment with sulfurylchloride, sulfonation, and other reactionsto which' hydrocarbons may besubjected.

Having thus described `our invention, what we claim is: l. In a processfor the production of apolymerhaving a molecular weight of at leastabout '300, the Ysteps vof contacting a normally ngaseous olefinselected from the 'class consisting of Lethylene", propylene'and.mixtures containing ethylene ,and propylene with the hydride of a metalselected from the group consisting of Be, Mg, Ca, Sr and'Ba and an oxideof aV metal of group 6a of the Mendeleef Periodic Table at 'a reactiontemperature beytweensabout .7.5. C. ,andzabout 325 C., and separatingY`.a polymer having a molecular weight of at least about group consistingof Be, Mg, Ca, Sr and Ba and an oxide of a metal of group 6a of `theMendeleef Periodic Table Y in the presence of a` liquid hydrocarbonreaction medium at a reaction temperature between about 75 C. and about`325 C., and separating a normally solid, resinous hydrocarbon materialthus produced.

5. The process of claim 4 wherein said oxide is partially pre-reducedbefore use.

6. The process of claim 4 wherein said liquid hydrocarbon reactionmediumis a saturated hydrocarbon.

7. The process of claim 4 wherein said liquid hydrocarbon reactionmedium is a monocyclic aromatic hydrocarbon. t

8. In a process for the production of a normally solid, resinoushydrocarbon material, the steps of contacting ethylene with the hydrideof a metal selected from the group consisting of Be, Mg, Ca, Sr and Baand an oxide of a metal selected from the group consisting of chromium,molybdenum and tungsten in the presence of a liquid hydrocarbon reactionmedium at a reaction temperature between about 75 C and about 325 C.,and separating `a normally solid, resinous hydrocarbon material thusproduced.

9. The process of claim 8 wherein the concentration of ethylene relativeto said liquid hydrocarbon reaction medium is between about 2 and about10 percent by weight.

10.` The processol` claim 9 wherein said oxide is partially pre-reducedbefore use.

11. In a process for the production of a normally solid, resinoushydrocarbon material, the steps which comprise contacting ethylene in aconcentration between about` 2 weight percent and about 10 weightpercent in a liquid `hydrocarbon reaction medium with the hydride of ametal selected from the group consisting of Be, Mg, Ca, Sr

and Ba and a catalyst comprising a minor proportion of an oxide of ametal selected from the group consisting of chromium, molybdenum andtungsten supported upon a major proportion of a diicultly reduciblemetal oxide, the ratio of said hydride to metal oxide catalyst beingbetween about 0.01 and about l0 by weight, at a reaction temperaturebetween about 130 C. and about 260 C.

`and a reaction pressure between about 200 and about 5000 p. s. i. g.,and separating a normally solid, resinous hydrocarbon material thusproduced. l

12. The process of claim 11 wherein the hydride is calcium hydride, theliquid reaction medium is benzene and the metal oxide is a pre-reducedmolybdenum oxide supported by gamma-alumina.

13. The process of claim 1l wherein the hydride is barium hydride, theliquid reactionmedium is xylene and the metal oxide is a pre-reducedchromium oxide supported by gamma-alumina.

14. A process for the preparation of a tough, resinous, normally solidpolymer, which process comprises contacting ethylene in a concentrationof at least about 2 weight percent but not more than about 10 weightpercent in a liquid hydrocarbon reaction medium with calcium hydride anda catalyst comprising a major proportion of a dificultly reducible metaloxide and a minor proportion of a partially pre-reduced molybdenum oxidehaving an average valence state between about 2 and about 5.5 at areaction temperature between about 230 C. and about 275 C. and areaction pressure between about 200 and about 5000 p. s. i. g., andseparating a solid polymer thus produced. Y

l5. The process of claim 14 wherein said liquid hydrocarbon reactionmedium is benzene, said molybdenum oxide is supported upon gamma-aluminaand the CaHzrmolybdena catalyst ratio is between about 0.05 and about 10by weight.

. 16. A process for the preparation of a resinous material from ethyleneand propylene, which process comprises contacting ethylene and propylenewith a liquid hydrocarbon reaction medium, a hydride of a metal selectedsaturated hydrocarbon reaction medium, calcium hydride,

a supported, partially pre-reduced group 6a metal trioxide, the weightratio of said calcium hydride to said supported group 6a metal trioxidebeing between about 0.05 and about l0, at a temperature between about C.and about 325 C., and separating a tough, resinous, hydrocarbonaceousmaterial thus produced.

18. ln a process for the production of a normally solid hydrocarbonmaterial, the steps which comprise contacting propylene and a liquidhydrocarbon reaction medium with the hydride of a metal selected fromthe group consisting of Be, Mg, Ca, Sr and Ba and a catalyst comprisinga minor proportion of an oxide of a metal selected from the groupconsisting of chromium, molybdenum and tungsten supported upon a majorproportion of a diicultly reducible metal oxide at a reactiontemperature between about 75 C. and about 325 C. under elevatedpressure, and separating a normally solid hydrocarbon material thusproduced.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A PROCESS FOR THE PRODUCTION OF A POLYMER HAVING A MOLECULARWEIGHT OF AT LEAST ABOUT 300, THE STEPS OF CONTACTING A NORMALLY GASEOUSOLEFIN SELECTED FROM THE CLASS CONSISTING OF EHTYLENE, PROPYLENE ANDMIXTURES CONTAINING ETHYLENE AND PROPYLENE WITH THE HYDRIDE OF A METALSELECTED FROM THE GROUP CONSISTING OF BE, MG, CA, SR AND BA AND AN OXIDEOF A METAL OF GROUP 6A OF THE